Industrial and institutional processes often produce fumes required to be exhausted and removed from the immediate area of the building. Exhaust systems include ducts, hoods, and exhaust fans to extract the contaminated fumes. Specific applications, such as laboratory or processing exhaust, are hazardous and must be exhausted to insure the safety of those working in close proximity to the source of the exhausted effluent. Safety concerns extend not only to those in the immediate area where the fumes are generated, but also to others located in the building as well as occupants in surrounding buildings.
Improperly designed exhaust systems that ineffectively discharge high concentrations of effluent can result in entrainment of the hazardous or noxious exhaust into the building air conditioning system, contaminating the fresh air brought into the building.
Problems are encountered in particular where the contaminated exhaust is heavier than air, is corrosive or has a foul odor. In these instances it is necessary to displace the exhaust at a height allowing dispersement to negate the possibility of concentration of the effluent at ground level.
In applications where exhaust needs to be displaced high above ground level, exhaust fans and stacks are typically placed on roof tops. To insure the displacement at levels high above ground level, it is known to use long exhaust stacks having an exit orifice at the desired height. Often, the stacks are so long as to be unstable and require the use of guy wires or other braces to ensure their stability, especially if high wind conditions are ever expected.
There is a need in the prior art for an improvement in the design of a fan and stack to deliver fumes to a maximum possible height, before dispersion of the exhaust within the environment occurs to allow complete dissipation and prevent concentration and contamination of the buildings at lower levels.
It is an object of the invention to provide an exhaust fan having a high plume height.
It is another object of the invention to have an exhaust fan having a compact configuration.
It is yet another object of the invention to provide a exhaust fan requiring low energy but having a high exhaust velocity.
It is another object of the invention to provide an exhaust fan allowing dispersement at a height preventing exhaust from reentering a building through an air conditioning system or other roof mounted equipment.
It is still another object of the invention to allow dispersement of exhaust eliminating costly corrosion caused by exhaust vapors.
It is another objective of the invention to provide an exhaust for diluting the exhaust before exiting the exhaust stack.
These and other objects of the invention will become apparent to one of ordinary skill in the art after reviewing disclosure of the invention.